The invention relates to a two-component binder which is suitable for surface coating compositions.
In DE-A-37 13 511 two-component paint binders based on methacrylic acid-2-acetoacetoxy-ethyl esters and their reaction products with aldehydes or ketones and amines are described. These systems cure very slowly at room temperature, however, and lead to yellow-coloured products.
In EP-A-0 160 824 two-component paints based on reaction products of compounds having CH-acid groups with olefinically unsaturated compounds are described. Enamines are not mentioned as CH-acid compounds. These systems cure insufficiently at room temperature and are therefore unsuitable for repair painting in the motor vehicle sector in workshops which have no stoving installations.
Two-component surface coatings curable by heating, based on CH-acid compounds and compounds with at least two .alpha.,.beta.-unsaturated groups, are also described in EP-A-0 224 158. Used there as CH-acid compounds are compounds containing methane tricarboxylic acid amide groups.
In EP-A-0 203 296 an isocyanate-free two-component binder system is described, which depends on the reaction of olefinically unsaturated compounds with blocked polyamines. This system can indeed be cured at room temperature, but resistance to gasoline and hardness of the system are reached only slowly; also gloss and flow of the surface are not satisfactory.
This problem is solved by the binder defined according to the claims.